JPS58137772A - Fixture used for circuit substrate test system - Google Patents

Abstract

PURPOSE:To perform the test for various print circuit (PC) plates, by using a substrate provided with probes at all test points and a plate provided with through holes corresponding to PC plates to be tested and bringing only required probes into contact with the PC plate to be tested. CONSTITUTION:A fixture body consists of a vacuum well 5, which is provided with test probes and consists of insulating materials, and a supporting plate 30 which is arranged vertically changeably in parallel with an upper face 29 of the well 5. Test probes provided on the well 5 are arranged in accordance with all test points of a preliminarily determined number of kinds of PC board pattern. When the supporting plate 30 is arranged in the well 5, all test plates can received into through holes of the supporting plate 30. An adapter plate 35 is arranged freely attachably and detachably on the supporting plate 30. The adapter plate 35 is provided with apertures 37 and 38 corresponding to test points of a specific PC board pattern to be tested, and other unused test probes are intercepted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixture used in a circuit board test system for testing a circuit board! This article relates to a 1-Cl universal type fixture commonly used for various circuit board patterns.

In recent years, on the production line of printed circuit boards (PC boards), ICs, LSIs, resistive elements, etc. are mounted on the finished products.
In addition, printed circuit board test systems that use computers to inspect whether each component of a PC board satisfies design specifications, whether correct circuit connections are made, etc. are becoming popular. This type of test system usually places a test culm PC board 2 on a fixture 1 as shown in FIG. Then, according to the test program, characteristic tests, such as resistance value tests and short circuit tests, are performed between selected test points to detect failure locations.

In this type of fixture, the test points on the PC board 2 and the test probes 3 have a corresponding positional relationship,
That is, the test probe 3 must be placed directly below the test point, and the positional relationship must be such that the test probe 3 comes into contact with the test point during inspection. Therefore,
The arrangement configuration of the test probes differs according to the pattern (component arrangement) of the PC board 2. Older fixtures had a fixed configuration of test probes, so they could only be used with specific PC board patterns. For this reason, it was inspected! When the number of patterns on the riC board increases, the same number of fixtures are required, which is very inconvenient in terms of installation space and cost.

In order to improve such old-style fixtures, conventionally, for multiple types of predetermined PC board patterns, only the face plate was replaced, and the fixture itself was commonly used. I tried to
A so-called universal type fixture has been developed. FIGS. 2A and 2B are cross-sectional views showing the structure of this universal fixture. FIG. 2A shows the released state before and after an inspection, and FIG. 2B shows the operating state during the inspection.

In this fixture 1, the well 5 of the main body has test probes (second
In Figures A and B, only three test probes 6.7.8 are shown) are implanted. Each test probe is inserted into the socket parts 6α, 7α, 8α fixed to the well 5, and the probe bins 6b, 7b, Bb are connected to each other.
Each probe bin is supported by a compression spring (not shown) disposed at the inner bottom of the socket portion. The terminals 5C, 7c, f3c of each test probe are connected to the wiring post 14 of the contact panel 13 (FIG. 1) via lead-in wires 10, 11, 12 wound around and connected thereto. The wiring posts 14 are arranged corresponding to test points on the PC board to be tested, and are connected to a common bus of the computer via a receiver and a switching matrix (not shown).

Above the well 5, a top plate 15 is provided with a compression spring 16.
It is removably supported via the . This top play) 15
In 1C, probe through-holes 17 and 18 are provided at positions corresponding to test probes 6 and 7 used for the specific PC board pattern to be inspected, and probe through holes 17 and 18 are provided at positions corresponding to test probes 8 that are not used. A counterbore hole 19 for storage is provided. This allows the second
As shown in the figure, the probe bins 6b, 7b of the used test probe 6.7 are connected to the through holes 17.1 of the upper plate 15.
8 through the corresponding test point 20 on the back of the PC boat.
21 but the probe bin 8 of the unused probe 8
h is kept in contact with the upper end surface of the counterbore hole 19 and not in contact with the back surface of the PC board.

A metal holding frame 23 is screwed onto the upper end of the peripheral part 22 of the well 5 to hold the top plate 15 from above when it is released as shown in FIG. 2A, and when this holding frame 23 is removed, the bottom side The top plate 15 of is removable. This removable top plate 15 is replaced according to the pattern of the PC board before being tested. In other words,
If the pattern of the PC board before being tested is different, remove the current top plate (15) and install another top plate corresponding to the different pattern, that is, the test probe used for the pattern. Another -L additional plate is attached which has probe through holes at positions and probe housing counterbore holes at positions corresponding to test probes not used for the pattern. and,
The fixture body is commonly used as it is to perform desired PC board inspections.

Although the universal type fixtures described above are a great improvement over older style fixtures, they still have various inconveniences. For example, in this conventional universal type fixture, it is necessary to replace the top plate depending on the pattern of the PC board to be inspected, but this top plate is quite heavy (several tens of kilograms) and requires a lot of work to replace. Further, in order to facilitate handling of this heavy top plate, a knob 24 is usually attached to the top of the heavy top plate, but this knob 24 increases the storage space of the top plate. Additionally, there are drawbacks in the manufacturing of the top plate. Today's general PC boards are equipped with a large number of IC1LSI etc. due to advances in semiconductor integrated circuit technology, and the number of test points has also become extremely large (usually on the order of several hundred, but can increase to several dozen). ). In the top plate used for such a PC board, it is actually extremely difficult and complicated to provide through holes for used test probes as well as counterbore holes for unused test probes, and requires careful technique.

Moreover, since the number of upper plates is equal to the number of patterns, this inconvenience increases as the number of patterns increases. In addition, there is also a great inconvenience when the design of the PC board is changed. For example, suppose that one component is added to a certain PC board pattern and the number of test points increases by one. in this case,
One additional test probe is implanted in the well at a position corresponding to the additional test point, and one probe through hole is drilled in the associated top plate for passing the additional test probe. However, since this additional test probe is an unused test probe for other PC board patterns, each of the remaining (nine in the above example) top plates has a counterbore hole to accommodate this additional test probe. This work is much more difficult than drilling the probe through hole.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a universal fixture that solves the above-mentioned problems, is easy to manufacture and handle at low cost, and can easily accommodate changes in the design of PC board patterns.

The fixture of the present invention has a predetermined number of types of P
(All test points of C board pattern) A board member (e.g. vacuum well) on which a number of test probes corresponding to VC are attached at positions corresponding to each test point,
A support plate is provided that is disposed substantially parallel to the upper surface of the substrate member so as to be movable in the vertical direction, and has a through hole for receiving each test probe. According to the invention, therefore:
All test probes are accommodated in the through holes of the support plate. Further, according to the present invention, an adapter plate having an opening at a position corresponding to a test probe used for a specific PC board pattern is removably disposed on the support plate, and the specific pattern is mounted on the adapter plate. PC boards to be inspected are placed. During testing, the support plate is moved to a lower position so that the test probes in use contact the test points on the back side of the PC board through the openings in the adapter plate. Also, when released before and after testing, the support plate is displaced to an upper position so that none of the test probes comes into contact with the back side of the PC board. In the present invention configured in this way, only the adapter plate needs to be replaced for different types of PC board patterns, and the fixture main body including the support plate can be used in common. The adapter plate according to the present invention can be made significantly smaller and lighter than the top plate in a conventional universal fixture, and is extremely easy to handle such as replacement, and requires less storage space. Furthermore, it can be manufactured at low cost, and changes in the PC board pattern can be easily handled with simple machining.

Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 3 and 4. In addition, Fig. 3A.

In B, parts corresponding to those in FIGS. 2A and B are given the same reference numerals.

According to a preferred embodiment of the invention, the fixture body comprises:
It consists of a vacuum well 5 made of an insulating material in which a test probe is implanted, and a support plate 30 disposed substantially parallel to the upper surface 29 of the well 5 and movable in the vertical direction.

The test probes implanted in the well 5 are arranged in a configuration corresponding to all test points of a predetermined number of types (for example, 10 types) of PC board patterns. The support plate 30 is fitted onto the inner circumferential surface 31 of the well 5 so as to be movable in the vertical direction, and is supported by the well 5 via a plurality of compression springs 16 . The support plate 30 is made of an insulating material, for example, glass epoxy resin, and has probe through holes at positions corresponding to the respective test probes. Therefore, when the support plate 30 is placed in the well 5,
As shown in Figure 3A, all test probes (3
The test probes 6.7.8 (only shown) are received in the corresponding through holes (32, 33, 34) of the support plate 30. An adapter plate 35 is removably arranged on the support plate 30. This adapter plate 35 has a slightly smaller shape than the pre-test PC board 2 placed directly above it.

Support plate 3 around the periphery of adapter plate 35
A sealing gasket 36 made of sponge is placed on top of the
When released as shown in FIG. 3A, the PC board 2 is placed on this gasket 36. adapter plate 35
are provided with openings 37, 38 corresponding to test points of a certain pre-test PC board pattern. As a result, when the adapter plate 35 and the pre-test PC board 2 are arranged and positioned, the test probe 6 used for testing the PC board 2 can be moved as shown in FIG. 3A.
．． The probe pins 6h, 7b of 7 face the corresponding test points 20.degree. 21 through the openings 37.38. On the other hand, the probe pin 8b of the test probe 8, which is not used for testing the PC board 2, faces the bottom surface of the adapter plate 35.

The top surface of the adapter plate 35 and the top surface 29 of the well 5
A plurality of disk-shaped hard rubber stoppers 40 and 41 are respectively arranged at appropriate positions.

A sealing gasket 42 made of rubber is fixed around the upper surface of the support plate 30 . A vacuum port 45 communicating with the well interior space 43, 44 is provided on the lower side of the peripheral portion 22 of the well 5. The space 43 between the support plate 30 and the upper surface of the well 5 and the space 44 between the PC board 2 and the adapter plate 35 when released before and after inspection as shown in FIG. 3A.
Each is filled with air. At this time, the support plate 30 is urged upward by the compression spring 16 and is in a device constructed from above by the holding frame 23 (FIG. 3A), and the PC board 2 is supported on the gasket 36. When performing an inspection, the well internal spaces 43 and 44 are evacuated through the vacuum port 45 using a vacuum pump (not shown). As a result, the support plate 30 is sucked downward against the compression spring 16 and is displaced to a position where it is seated on the upper surface of the stopper 41 (FIG. 3A). At the same time, the PC board 2 is also sucked downward against the deformation elastic force of the gasket 36, and as a result, the back surface of the PC board 2 is seated on the top surface of the stoppers 40 and supported by the adapter plate 35 via these stoppers 40. and the test points) 38, 39 respectively correspond to the corresponding used test probes 6.
7 probe pin 6h.

Contact 7h. The contact pressure between these test points and the glove bin depends on the height of the stopper 40, 41 or the elastic force of a compression spring (not shown) disposed in the test probe socket that biases the probe pin upward. The desired size can be selected by adjusting. On the other hand, at this time, the probe pin 8b of the unused test probe 8 is brought into contact with the bottom surface of the adapter plate 35 due to the downward movement of the support plate 30 and the adapter plate 35, and is pressed further downward, sinking to the position shown in FIG. 3. As a result, a non-contact relationship between the unused test probe and the back surface of the PC board is reliably maintained.

Any material can be selected for the adapter plate 35 as long as it is an insulating material that is strong enough to withstand the pressing force of unused probe pins during inspection and is suitable for machining. In this example, the adapter plate 3 is made from transparent glass epoxy resin.
Make 5. The thickness of the adapter plate can be selected from various sizes, and it is advantageous to make it as thin as possible in terms of production costs and drilling work, but on the other hand, the probe pins may penetrate from below during multiple inspections. It is desirable that the thickness be such that there are no scratches.

FIG. 4 is a top perspective view of the adapter plate 35 and support plate 30. A number of probe through-holes 50 in support plate 30 are arranged to receive all test probes attached to the wells. On the other hand, the plurality of openings 51 formed in the adapter plate 35 are arranged to correspond to the test points of the PC board to be tested or the test probes used to test the PC board. The aperture 51 is thus positioned directly above the probe through-hole that accommodates the test probe in use. Since the adapter plate 35 is transparent, its positioning is easy. That is, since it can be easily seen from above whether each opening 51 is directly above the corresponding probe through-hole 50, the adapter plate 35 can be placed over the support plate 30 accurately and quickly. This makes the work of attaching the adapter plate easier and is also advantageous for changing the design of the circuit pattern. That is, when the number of test points increases, it is convenient to simultaneously drill additional through holes at predetermined positions in the support plate 30 and the well 5 from above through the transparent adapter plate 35.

Although one embodiment of the present invention has been described above in connection with FIGS. 3 and 4, various modifications and changes can be made in accordance with the technical idea of the present invention. For example, the above-mentioned embodiment is a vacuum type fixture that vacuums the sealed space inside the well and suctions and displaces the support plate and PC board downward during inspection, but other electromagnetic or mechanical type fixtures may be used. The present invention is also applicable to. In that case, no special sealing structure is required, and the sealing gasket 36, 42, vacuum port, etc. may be omitted. Further, the shapes of the well, the support plate, and the adapter plate can be changed as appropriate depending on the type of PC board to be tested, the type of the test probe, and the like.

As mentioned above, in the present invention, many types of PCs to be tested
Only the adapter plate needs to be replaced for the board pattern. Conventional universal type fixtures require replacement of the top plate, but this top plate has a shape and structure that corresponds to the well, making it considerably large and heavy, making replacement work troublesome and requiring a large amount of storage space.

In contrast, in the present invention, the support plate, which is substantially parallel to the top surface of the well and is displaced in the vertical direction, has a shape and structure corresponding to the well, and the adapter plate has a shape and structure corresponding to the PC board to be inspected. Bye. Therefore, the adapter plate according to the present invention can be formed to be significantly smaller and lighter than the conventional top plate, and is extremely easy to handle such as replacement, and requires a small storage space. Furthermore, in the present invention, the unused test probe is connected to the PC to be tested.
Since there is no need to provide counterbore holes to prevent contact with the back side of the board, manufacturing and modification are easy.Especially when the adapter plate is made of transparent material, installation work, drilling work, etc. are easier. It is even more advantageous.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing a fixture used in a conventional circuit board test system, FIGS. 2A and 2B are cross-sectional views illustrating the structure of a conventional universal type fixture, and FIGS. B is a sectional view for explaining the structure of a fixture according to an embodiment of the present invention, FIG. 3A is a diagram showing the released state before and after inspection, and FIG. 3B is a diagram showing the operating state at the time of inspection. The figures shown and FIG. 4 are as shown in FIG. 3A,
FIG. 3 is a top perspective view of the support plate and adapter plate in FIG. 2... Printed circuit board (PC board), 5
... Vacuum well, 6.7.8 ... Test probe, 20.21
...... Test point, 30... Support plate, 32.33.34... Probe through hole, 35
・・・・・・ Adapter plate, 37.38・・・・
・・Opening. Patent applicant MI Technical Service Co., Ltd. 5”'-1 Agent Patent attorney Kyo Yu Asa 3 41-+, - (2 others) Izumi/ Figure 2 A Rod, Figure 2 B

Claims (1)

[Claims] +11 In a fixture used in a circuit board test system for inspecting circuit boards, a number of test probes corresponding to all test points of a predetermined number of types of circuit board patterns are connected to each of the test points. a substrate member mounted at a position corresponding to the substrate member, a support plate disposed substantially parallel to the upper surface of the substrate member so as to be displaceable in the vertical direction, and having a common through hole for receiving each of the test probes; an adapter plate for mounting the circuit board, the adapter plate being removably disposed on the support plate and having an opening at a position corresponding to the test probe used for the specific circuit board; each said test probe does not contact the backside of said circuit board when in an upper first position;
When the support plate is in the lower second position, the used test probe contacts a predetermined test point on the back side of the circuit board through the opening of the adapter plate. Fixture with f'2. (2) The fixture according to claim 1, wherein the adapter plate is made of transparent insulating material.